关键词:  YD油田, 延长组,  , 成岩作用,  , 成岩演化序列, 成岩阶段, 孔隙演化

Abstract: Based on the research of sandstone slice samples and its petrological characteristics in Chang 4+5，Chang 6 sandstone reservoir of YD oilfield, diagenesis and the influence degree of diagenesis on porosity and permeability of reservoir were studied. Diagenetic evolution sequence in Chang 4+5，Chang 6 sandstone reservoir was established and diagenetica stage, pore evolution of the study area were devided. The results indicated that sandstone diagenesis this area was strong and abundant. Mechanical compaction, pressure solution, cementation and metasomatism were the key factors which led to loss of the primary pores in Yanchang Group sandstone reservoir. Also, the above factorsresulted in flow ability lost of acidic ground fluids, which made dissolution become poor and reservoir become particularly tight. According to the classification discipline of clastics diagenesis phase, the sandstone of Yanchang Group experienced sorts of diagenesis, where its intensity was significant and was now in the early period of late diagenetic (A). Sandstone pore had experienced many evolution processes, which were the initial pore slashed. A small amount of residual intergranular pores was retained and all kinds of pores gradually developed into corrosion pores. Diagenesis in upper Chang 4+5 was more favorable for hydrocarbon transfusion and reservoir.

Key words: YD Oilfield,     ,  Yanchaug group,     ,  Diagenesis,     ,  Diagenetic evolution sequence,    ,  Diagenetic stage,    ,  Pore evolution